Cantilever loading drawer rail and assembly



June 10, 1969 J. PIPE CANTILEVER LOADING DRAWER RAIL AND ASSEMBLY Sheet INVENTOR. /U/l/V P/PE Filed Dec. 11, 1967 ATTORNEYS United States Patent 3,449,033 CANTILEVER LOADING DRAWER RAIL AND ASSEMBLY John Pipe, Grand Rapids, Mich., assignor to Steelcase,

Inc., Grand Rapids, Mich., a corporation of Michigan Continuation-impart of application Ser. No. 497,266,

Oct. 18, 1965. This application Dec. 11, 1967, Ser.

Int. Cl. A47b 88/10; F16c 35/02 U.S. Cl. 312-339 3 Claims ABSTRACT OF THE DISCLOSURE Cross reference to related application I This is a continuation-impart application of my copending application entitled Cantilever Loading Extensible Drawer Rail, Ser. No. 497,266, filed Oct. 18, 1965, and sets forth an improvement on the apparatus therein.

Background of the invention This invention relates to drawer rail assemblies, and more particularly to telescoping drawer rail assemblies having unique cantilever loading action On the rails to achieve and retain optimum alignment between the rails.

Conventionally, each 'of the two slide rail assemblies employed in mirror image position on opposite sides of a drawer, between the drawer and the cabinet or case, includes telescopically interfitting rails allowing extension therebetween for drawer extension and retraction. Minimum friction is normally obtained by the use of rolling elements such as rollers or balls between the rails. Typically, a rail assembly includes a case rail for mounting to the inside wall of a cabinet, a drawer rail formounting to the outer wall of a drawer, and an intermediate rail telescopically mounted between the drawer rail and the case rail, and allowing relatively full extension of the drawer rail and the drawer attached thereto. If desired, a.

or else rail scraping etc. will normally occur almost constantly.

Efforts to improve their structural characteristics have included those to control the lateral movement of the 'balls by controlling the manufacturing tolerances of the rail members to very critical values, or alterna ively by slightly concavely curving the upper and lower ball track surfaces on the rails. Control of tolerances has a very real practical limit however, and is only partially effective anyway. The concave dishing of the upper and lower track surfaces, although an improvement, is also definitely limited by the narrow breadth of the tracks, so that it is only partially effective in actual practice. Both of these techniques also necessitate considerable added manufacturing cost.

' Summary of the invention It is an object of this invention to provide a novel drawer rail assembly that uniquely employes the torsional force of cantilever loading to constantly retain the rails in optimum alignment.

Another object of this invention is to provide a drawer rail asembly achieving excellent rail alignment resulting in practically no side sway of the drawer and assembly, even at full extension of the rail assembly. Moreover, this is achieved without special close tolerances for rail parts,

and without complicated dishing of the rail track surfaces.

Another object of this invention is to provide a novel cantilever loading drawer rail assembly that eliminates the direct scraping tendency between the rail members themselves, even when approaching full extension. The unit is therefore extremely quiet in operation, and has minimum friction. g ii Another object of this invention is to provide a drawer rail assembly achieving minimum friction movement by assured loading each individual ball in the assembly on a vertical axis through each ball and also on a horizontal axis through the ball, with these axes being normal to each other.

Another object of this invention is to provide a drawer rail assembly that achieves smooth quiet action even if not mounted on a horizontal plane, enabling the drawer to be mounted even on angles of up to about yet vertical and lateral loading on each of the individual progressive propulsion roller may be mounted on the intermediate rail for contact on its periphery directly can have a vertical or a horizontal axis.

Generally, the supportbetween the rails is achieved by.

a first plurality of balls retained between the case rail and the intermediate rail, and a second plurality'of balls retained between the intermediate rail and the drawer rail.

This basic known structure efiectuates a fairly good limited friction suspension assembly. Such a structure has shortcomings however, with a well known one being the difliculty of keeping the slides aligned vertically without lateral .play. This play allows scraping contact between the rails themselves, thereby increasing the friction, and consequently increasing the operating force required to extend and retract them, as well as increasing the noise level. The conventional structure also allows considerable side sway of the opened drawer and extended rail assemblies. As a result, care must be taken to mount the rail assemblies exactly so that they are horizontally aligned,

balls with torsional. force applied during assembly. The drawer rails of the rail assemblies are so constructed, configurated, and arranged as to be forcefully distorted against an inherent bias during assembly to achieve this. The three rails of each rail assembly define generally square-ball tracks between them, two tracks between the case rail and the intermediate rail, and two tracks between the intermediate-rail and the drawer rail. Each drawer rail has a downwardly-inwardly cocked orientation in its freev state, and having a pair of laterally offset, upper and lower Ls-connected head to to e, i.e.

These and several other" objects of this invention will become apparent upon studying the following specification in conjunction with the drawings.

Brief description of the drawings FIG. 1 is a side elevational view of the first form of the drawer rail assembly, shown in its retracted condition;

FIG. 2 is a side elevational view of the assembly in FIG. 1, shown extended;

FIG. 3 is an enlarged sectional view of the two of the drawer rail assemblies like the one in FIG. 1, as taken plane III-III in combination with a drawer and a case;

FIG. 4 is a side elevational view of a second form of the novel drawer rail assembly, shown in a retracted condition;

FIG. 5 is a side elevational vie-w of the assembly in FIG. 4, shown extended; and

FIG. 6 is an enlarged sectional view of the assembly in FIGS. 4 and 5, taken on plane VI-VI of FIG. 4, shown with a case.

The term inwardly when used herein, refers to a direction toward the drawer to be mounted, and away from the case panel. The term outwardly means the opposite.

Referring now specifically to the drawings, the first drawer rail assembly 10 illustrated in FIGS. l-3 includes a case rail 12, an intermediate rail 14, and a drawer rail 16.

Case rail 12 has an elongated, vertically oriented back panel 20 for mounting to the inside vertical wall of a cabinet or case into which the drawer is to extend. In tegral with this panel is a horizontally inwardly extending upper panel leg 22, from which depends a flange 24 extending downwardly parallel to panel 20 and terminating short of intermediate rail 14. Case rail 12 also includes a bottom horizontally inwardly extending leg panel 26 parallel to panel 22, and normal to back panel 20, with a lower, depending, downwardly extending flange 28 integral therewith at its outer edge.

Telescopically interfitting within case rail 12 is intermediate rail 14. This intermediate rail includes a main elongated vertical panel 30, having an inwardly extending horizontal upper flange 32. Welded to this flange is a somewhat Z-shaped member that includes a horizontal leg 34 secured to panel 32, (as by welding so as to be integral with it), an inner downwardly extending flange 36, parallel with back panel 20, and an upwardly extending outer flange 3-8 above and laterally offset from flange 38. Flange 38 is parallel to and adjacent panel 20 and is parallel to, but on the opposite side of the ball track from flange 24 of case rail 12. Near to but spaced from the bottom flange 26 of case rail 12, intermediate rail 14 has a horizontally inwardly, extending panel 40, a downwardly depending retaining panel 42 extending therefrom and parallel to back panel 20.

- Drawer rail 16 interfits telescopically in intermediate rail 14. It has two laterally offset vertical panels, one above the other, and two vertically offset horziontal panels arranged in the shape of two Ls, with the toe of one attached to the top of the other. It includes a vertically extending panel 50, an outwardly extending horizontal panel 52 extending therefrom, and a vertically extending outside panel 54 extending up from panel 52 inside case rail 14. This drawer rail includes horizontal panel 56 extending inwardly from the bottom edge of panel 50 to engage the drawer bottom as a loading platform.

Briefly therefore, case rail12 is generally C-shaped in cross section, but having a pair of downwardly extending inner flanges, both extending in the same direction, from the two legs of the C; drawer rail 16 is double L-shaped, with one L being attached to and depending from the first L; and intermediate rail 14 has a generally C-shaped central portion, with a depending flange portion attached to its lower leg, and a generally Z-shaped member mounted to the top of its upper leg.

These three rails define four square ball tracks or raceways. Each receives a plurality, normally two, spherical balls. The four raceways are arranged vertically, one

above the other. Upper raceway has opposite horizontal upper and lower ball engaging, bearing walls or surfaces 22 and 34 of the case rail and intermediate rail, and has opposite vertical side bearing walls or surfaces 38 and 24, all arranged in a square configuration to abut the retained balls on both a vertical axis and a horizontal axis. The next lower raceway 66 also has opposite upper and lower surfaces 32 and 52 of the intermediate rail and'drawer rail, and opposite side surfaces 54 and 36 of the drawer rail and intermediate rail. The third raceway 72 has opposite upper and lower surfaces 52 and 40 of the drawer rail and intermediate rail and opposite side surfaces 50 and 30 of the drawer rail and intermediate rail. The fourth and lowermost raceway 78 has oppoosite upper and lower surfaces 40 and 26 of the intermediate rail and case rail and opposite side surfaces 20 and 42 of the case rail and intermediate rail. Each raceway is square and has four bearing surfaces. One vertical and one adjacent horizontal surfaces are of another rail. Raceway 60 between the intermediate rail and the case rail confines balls 62 and 62', raceway 66 between the topof the drawer rail and thet intermediate rail confines balls 68 and 68', race-way 72 between the bottom of the drawer rail portion and the intermediate rail includes balls 74 and 74, and raceway 78 between the bottom of the case rail and the bottom of the intermediate rail includes balls 80 and 80. The case rail and intermediate rail form two raceways between them, and the intermediate rail and drawer rail form two raceways between them. The halls are each retained in their intended section of their raceways by suitable stops formed in conventional fashion as by depressing dimples, e.g. 61 (FIG. 1) into the rail member astraddle each ball. Since this is conventional, such stops are not described in detail.

When the assemblies are fully assembled, each squareshaped raceway of the first set of two between the case rail and intermediate rail has width and height dimensions substantially equal to the diameter of the spherical floating balls contained therein. Each ball is contacted on a vertical load axis with bearing surfaces which are directly opposed, and on a horizontal load axis on each side thereof against bearing surfaces which are directly 0pposed. The two axes of load, vertical and laterally horizontal are normal to each other. The two raceways or ball tracks of the second set between the drawer rail and the intermediate rail however are purposely slightly smaller than the balls in them, so that the drawer rail, in its free state, has a slightly downwardly-inwardly tilted or cocked relation of a few degrees with respect to the other members. The lower vertical panels 50 of the two drawer rails (FIG. 3) therefore extend slightly toward each other, and the horizontal drawer stop or platform panels 56 are cocked inwardly upwardly a like amount. These panels are slightly flexible, being normally formed of steel sheet stock, and have a resilient resistance against deformation so as to apply a biasing force when distorted or deformed. The elements are designed and arranged to be deformed with insertion of the drawer in a manner to be described hereinafter.

The multiple parts of the rail assembly, as illustrated in FIGS. 1 through 3, may be readily assembled by inserting the intermediate rail into the case rail with the balls therebetween, and by inserting the drawer rail into the intermediate rail with the balls therebetween. The intermediate rail may also be securely positioned with respect to 'the case rail to prevent them from normally being accidentally disassembled as by a small retainer flange member 86 in conventional manner.

When the appaeatus is put into use, the drawer rail assemblies 10 and 10A are mounted in mirror image fashion to the inner facing surfaces of a cabinet or case by securing panels 20 and 20A to the case C. The spacing between the rail assemblies is controlled with respect to the width of the drawer D to be mounted so that the space between the upper parts of panels 50 and 50A is I slightly greater than the drawer width, but the space between the lower parts of panels 50 and 50A is a fraction of an inch less than the drawer width to cause these panels to be flexibly distortionally bent outwardly to a position parallel with the other vertical panels of the rail assemblies and to cause platform panels 56 and 56A to become horizontal as the drawer is forced down into position (see phantom lines inFIG. 3). This cantilever loading creates a torsional force to be transmitted by the drawer rails to the other rails through the balls so that all four raceway walls of each raceway contact each ball firmly. The force removes any play" in the rail assemblies, to prevent lateral sway. The rail members themselves are retained securely out of contact with each other to prevent scraping and friction.

The same cantilever loading principle can be employed with slightly differently configurated rail members, More specifically, the modified rail assembly 110 illustrated in FIG. 4 includes a case rail 112, an intermediate rail 114, and a drawer rail 116. These rail members telescopically interfit to form a plurality of four raceways, each having a square cross sectional configuration of two opposite vertical walls of two different rail members contacting the spherical balls with bearing surfaces on opposite sides, to form a horizontal load axis, and two opposite horizontal walls contacting the spherical elements on top and bottom, to form vertical load axes. The overall configuration of the drawer rail member 116 is substantially like that illustrated in the first form of the invention, but it is assembled in different relationship with the intermediate rail. That is, its horizontal flange still extends between the balls to complete the two raceways for-med between the drawer rail and the intermediate rail, but in this instance these are the lowermost raceway and the next raceway thereabove, rather than the two central raceways as in the first form of the invention. The intermediate rail is shaped differently than in the first form of the invention, having a generally C-shaped lower portion and a backwards C-shaped upper portion integral therewith. The case rail basically is still C-shaped in cross sectional configuration, but having two upwardly extending flanges on the two legs of the C, rather than downwardly extending flanges.

The drawer rail 116 has two laterally offset vertical panels 150 and 154 which form two walls of two respective adjacent raceways, one horizontal panel 52 which forms'the bottom of one raceway and the top of a second raceway, and a horizontal inwardly extending loading platform flange 158 for engaging the bottom of a drawer. The case rail includes a main vertical back panel 120, an inwardly extending upper panel 121, the upper surface of which forms the bottom of a raceway, and an upwardly extending outer flange 123 forming the inside of the same raceway. It also includes a lower inwardly extending horizontal leg panel 126 and an upwardly extending flange 127.

Intermediate rail 114 includes an upper outwardly opening C-shaped portion with an upper horizontal leg 131, the bottom of which forms the top of a raceway, a vertical leg 133 forming one side wall of a raceway, and the lower leg 135 forming the bottom of another raceway. This lower leg has attached thereto an L-shaped member 137 which forms the top of a third raceway, as well as the inside wall thereof. Extending integrally downwardly from this leg 135 is a vertical leg 137 forming the wall of the lowermost raceway, and a horizontal leg 139 forming the bottom of the lowermost raceway.

If desired, a progressive actuating roller member 151 may be mounted on its horizontal axis to the intermediate rail, with the upper surface contacting the drawer rail, and the lowermost portion of the case rail for progressive actuation of the rails during extension and contraction.

Two balls are mounted in each of the raceways as illustrated in FIGS. 4 and 5, similar to the first form of the invention. That is, balls 162 and 162 are in raceway 160,

7 balls 168 and 168' in raceway 166, balls 174 and 174 in blies illustrated have been found to work effectively.

: Either of the assemblies enable drawers to be mounted off horizontal, even on an angle of up to about 45 or so, without side sway, without binding, without scraping between the rail members, and with smoothness and quietness of operation. The lateral loads applied with drawer tilting are not detrimental.

It is conceivable that certain additional modifications of individual rail construction may be achieved within the concept presented. Hence, the invention is intended to be limited only by the scope of the appended claims and the reasonably equivalent structures to those defined therein.

I claim:

1. A cantilever loading drawer rail assembly having a telescopically interfitting set of an outer case mount rail, an intermediate rail, and an inner drawer mount rail, said rails being configurated and arranged to form a first set of ball tracks between said case mount rail and said intermediate rail and a second set of ball tracks between said intermediate rail and said drawer mount rail, a plurality of 'balls in each of said ball tracks; said ball tracks being vertically arranged with respect to each other, and each of said ball tracks having a generally square configuration of a pair of opposite ball engaging lateral walls and a pair of opposite ball engaging upper and lower walls; said drawer rail having two laterally offset vertical panels, one below the other, interconnected by a cross leg panel, the upper panel forming an outer lateral wall of a first ball track of said second set, the lower panel forming an inner lateral wall of a second ball track of said second set, and said cross leg panel extending between the balls in said first and second ball tracks of said second set; and said drawer rail being cocked downwardly-inwardly at a small angle so as to require said lower panel to be laterally outwardly distorted a small amount against an inherent bias thereof with mounting of a drawer thereon, thereby causing .a torsional force to be applied by the rails to the balls during assembly for retaining all of the ball track walls in engagement with the respective balls.

2. A drawer and rail apparatus having a drawer mounted to a pair of mirror image cantilever loaded drawer rail assemblies; each drawer rail assembly having a telescopically interfitting set of .an outer case mount rail, an intermediate rail, and an inner drawer mount rail, said rails being configurated and arranged to form a first set of ball tracks between said case mount rail and said intermediate rail and a second set of ball tracks between said intermediate rail and said drawer mount rail, a plurality of balls in each of said ball tracks; said ball tracks being vertically arranged with respect to each other, and each of said ball tracks having a generally square configuration of a pair of opposite ball engaging lateral walls and a pair of opposite ball engaging upper and lower walls; said drawer rail having two laterally offset vertical panels, one below the other, interconnected by a cross leg panel, the upper panel forming an outer lateral wall of a first ball track of said second set, the lower panel forming an inner lateral wall of a second ball track of said second set and being resiliently bendable, and said cross leg panel extending between the balls in said first and second ball tracks of said second set; the said drawer rails in said drawer rail assemblies having their lower panels forcefully distorted apart by 7 8 said drawer from a base state condition cocked at a 1,566,307 12/1925 Card 312339 small angle toward each other, causing their resilience to 2,812,222 11/1957 I Gossack 3086 apply a torsional force to both drawer rail assemblies to 3,009,755 11/ 1961 Rackow 312339 forcefully retain all of the ball track walls into engage- 3,203,749 8/1965 Bullock et a1. 312-339 ,ment with the respective balls. 5

3. The apparatus in claim 2 wherein each of said 7 FOREIGN PATENTS drawer rails includes .a horizontal platform panel pro- 921,253 5/1947 Puma jecting from said lower panel toward the opposite drawer rail assembly and engaging the bottom of said drawer. EDGAR W,'GEOGHEGAN, P i E i 10 LUCIUS L. JOHNSON, Assistant Examiner.

" U.S. ci. X.R.

References Cited UNITED STATES PATENTS 1,135,235 4/1915 Weiss 312-639 

